Abnormality detection circuit for fire-fighting monitoring

Abstract

The utility model discloses an anomaly detection circuit for fire-fighting monitoring, which belongs to the field of circuit monitoring for fire-fighting monitoring, is arranged between a singlechip and a circuit to be detected, and comprises a power supply output control circuit and a state detection circuit, the power supply output control circuit is provided with an MOS tube VM1, a triode VT1 and a triode VT3, the base electrode of the triode VT3 is connected to the control / detection port, the collector electrode of the triode VT3 is connected with the grid electrode of the MOS tube VM1, and the base electrode and the collector electrode of the triode VT1 are respectively connected in parallel to the grid electrode and the source electrode of the MOS tube VM1; the state detection circuit is arranged between the power supply output control circuit and the single-chip microcomputer, the response speed of power supply control is improved through the combined structure of an MOS tube and a triode, meanwhile, the state detection circuit directly interacts with the single-chip microcomputer, a power supply can be rapidly cut off when the circuit is abnormal, a fault signal is fed back, and equipment damage caused by overcurrent or short circuit is avoided.

Description

Technical Field

[0001] The utility model belongs to the field of circuit monitoring for fire control, and specifically relates to an abnormal detection circuit for fire control monitoring. Background Art

[0002] With the complexity of modern building electrical systems, higher requirements are put forward for the real-time performance and reliability of circuit abnormal detection in fire control monitoring systems. Most traditional fire circuit monitoring devices use mechanical relays as power control elements, which are bulky and have limited response speed, and are prone to problems such as contact adhesion or oxidation failure under frequent start-stop conditions. The detection of abnormal states such as short circuits and overloads usually relies on simple voltage comparison circuits. Such solutions have detection blind spots, cannot effectively distinguish instantaneous interference from real faults, and it is difficult to achieve linkage control between power output and detection status. For example, the Chinese patent with the publication number CN221960432U discloses a fire safety monitoring circuit system, including a power supply system, a controller, an environmental parameter detection system, an equipment status detection system, and a human-computer interaction system; the output end of the controller is respectively connected to the input ends of a communication module, an environmental parameter detection system, an equipment status detection system, a human-computer interaction system, and an audible and visual indication module, and the power supply system is connected to the controller, the environmental parameter detection system, the equipment status detection system, the human-computer interaction system, and the audible and visual indication module for power supply.

[0003] The problem of delayed feedback of detection signals commonly existing in these prior arts is likely to cause the single-chip microcomputer to receive incorrect status information, and may cause secondary faults due to untimely response during overcurrent protection.

[0004] In view of this, this application is specifically proposed. Summary of the Utility Model

[0005] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide an abnormal detection circuit for fire control monitoring. The utility model is realized through the following technical solutions:

[0006] An abnormal detection circuit for fire control monitoring, the abnormal detection circuit is arranged between a single-chip microcomputer and a circuit to be detected, and includes a power output control circuit and a status detection circuit;

[0007] The power output control circuit is provided with a MOS transistor VM1, a triode VT1, and a triode VT3. The base of the triode VT3 is connected to a control / detection port, the collector of the triode VT3 is connected to the gate of the MOS transistor VM1, and the base and collector of the triode VT1 are respectively connected in parallel to the gate and source of the MOS transistor VM1;

[0008] The status detection circuit is arranged between the power output control circuit and the single-chip microcomputer.

[0009] Preferably, the power output control circuit includes a capacitor C2 and a resistor R3. The capacitor C2 is arranged at the front end of the resistor R3. One end of the capacitor C2 is connected to the input power supply VCC, and the other end is grounded. The resistor R3 is connected in parallel across the emitter and collector of the triode VT1.

[0010] Preferably, a capacitor C3 is connected in parallel between the emitter and base of the triode VT1. A resistor R5 is connected in series with the capacitor C3. A resistor R2 is connected in parallel with the capacitor C3 and the resistor R5. A capacitor C1 is connected in parallel with the resistor R2.

[0011] Preferably, the base and collector of the triode VT1 and the resistor R5 are connected in parallel between the gate and source of the MOS transistor VM1.

[0012] Preferably, a resistor R10 is arranged between the base of the triode VT3 and the power output point.

[0013] Preferably, a TVS diode VD4, a resistor R11 and a resistor R12 are connected in parallel between the base and emitter of the triode VT3;

[0014] A capacitor C6 is arranged between the power output point and the ground wire.

[0015] Preferably, the state detection circuit includes a resistor R1. The input end of the resistor R1 is connected to the single-chip microcomputer reference level. The output end of the resistor R1 is connected to the AD detection port after passing through a resistor R4. A grounded C4 is arranged between the resistor R4 and the AD detection port.

[0016] Preferably, a diode VD1 is further connected to the output end of the resistor R1. One end of the diode VD1 is connected to the resistor R1 and the resistor R4, and the other end is connected to a resistor R8. One end of the resistor R8 is connected to the diode VD1 and the drain of the MOS transistor VM1, and the other end is connected to the power output point.

[0017] Preferably, the state detection circuit further includes a TVS diode VD2, a TVS diode VD3, a resistor R7 and a triode VT2. The TVS diode VD2 and the TVS diode VD3 are connected in series and then connected in parallel across the resistor R8. The TVS diode VD2, the TVS diode VD3 and the resistor R7 are connected in series in turn and then connected in parallel across the emitter and base of the triode VT2.

[0018] Preferably, the state detection circuit further includes a resistor R6. One end of the resistor R6 is connected to the collector of the triode VT2, and the other end is grounded after passing through a resistor R9. A single-chip microcomputer detection pin is connected between the resistor R6 and the resistor R9;

[0019] A capacitor C5 is connected in parallel with the resistor R9.

[0020] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0021] 1. Through the collaborative design of the power output control circuit and the status detection circuit, real-time dual monitoring of the fire monitoring circuit is achieved. The combined structure of the MOS transistor and the triode improves the response speed of power control. At the same time, the status detection circuit directly interacts with the single-chip microcomputer, can quickly cut off the power supply and feedback a fault signal when the circuit is abnormal, avoiding equipment damage caused by overcurrent or short circuit, and significantly improving the reliability of the system.

[0022] 2. By setting the capacitor C2 and the resistor R3, the filtering performance of the power input is optimized. The capacitor C2 can absorb high-frequency noise, and the resistor R3 prevents the triode VT1 from being damaged due to instantaneous voltage fluctuations through current limiting, thereby ensuring the stability of the power output control circuit in a complex electromagnetic environment.

[0023] 3. By setting the parallel structure of the capacitor C3 and the resistor R5 to form an RC delay network, high-frequency oscillation during the switching process of the triode VT1 can be suppressed. The parallel connection of the resistor R2 and the capacitor C1 further filters out the noise in the base drive signal, avoiding mis-triggering and making the power control logic more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the circuit structure of the present utility model;

[0025] Figure 2 is a schematic diagram of the system connection of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The present utility model will be further described and illustrated below with reference to the accompanying drawings.

[0027] As Figure 1 shown, this embodiment provides an abnormal detection circuit for fire monitoring. The abnormal detection circuit is arranged between the single-chip microcomputer and the circuit to be detected, and includes a power output control circuit and a status detection circuit;

[0028] The power output control circuit is provided with a MOS transistor VM1, a triode VT1 and a triode VT3. The base of the triode VT3 is connected to the control / detection port, the collector of the triode VT3 is connected to the gate of the MOS transistor VM1, and the base and the collector of the triode VT1 are respectively connected in parallel to the gate and the source of the MOS transistor VM1;

[0029] The status detection circuit is arranged between the power output control circuit and the single-chip microcomputer.

[0030] Through the collaborative design of the power output control circuit and the status detection circuit, real-time dual monitoring of the fire monitoring circuit is achieved. The combined structure of the MOS transistor and the triode improves the response speed of power control. At the same time, the status detection circuit directly interacts with the single-chip microcomputer, can quickly cut off the power supply and feedback a fault signal when the circuit is abnormal, avoiding equipment damage caused by overcurrent or short circuit, and significantly improving the system reliability.

[0031] The power output control circuit includes a capacitor C2 and a resistor R3. The capacitor C2 is arranged at the front end of the resistor R3. One end of the capacitor C2 is connected to the input power supply VCC, and the other end is grounded. The resistor R3 is connected in parallel across the emitter and collector of the triode VT1.

[0032] By setting the capacitor C2 and the resistor R3, the filtering performance of the power input is optimized. The capacitor C2 can absorb high-frequency noise, and the resistor R3 prevents the triode VT1 from being damaged due to instantaneous voltage fluctuations through a current-limiting effect, thus ensuring the stability of the power output control circuit in a complex electromagnetic environment.

[0033] A capacitor C3 is connected in parallel between the emitter and the base of the triode VT1. The capacitor C3 is connected in series with a resistor R5. A resistor R2 is connected in parallel across the capacitor C3 and the resistor R5. A capacitor C1 is connected in parallel across the resistor R2.

[0034] By setting the parallel structure of the capacitor C3 and the resistor R5 to form an RC delay network, high-frequency oscillations during the switching process of the triode VT1 can be suppressed. The parallel connection of the resistor R2 and the capacitor C1 further filters out the noise in the base drive signal, avoiding mis-triggering and making the power control logic more accurate.

[0035] Furthermore, a resistor R5 is connected in parallel between the base and the collector of the triode VT1 and the gate and the source of the MOS transistor VM1. By directly connecting the base and the collector of the triode VT1 in parallel to the gate and the source of the MOS transistor VM1 to form a negative feedback loop, the on-resistance of the MOS transistor can be dynamically adjusted, reducing the switching loss and suppressing voltage spikes, thereby prolonging the service life of the power device.

[0036] Preferably, a resistor R10 is arranged between the base of the triode VT3 and the power output point.

[0037] The addition of the resistor R10 provides a stable bias voltage for the base of the triode VT3, avoiding misoperation of VT3 due to fluctuations in the control / detection port level, and at the same time limiting the base current to prevent device damage caused by over-driving.

[0038] Furthermore, a TVS diode VD4, a resistor R11, and a resistor R12 are connected in parallel between the base and the emitter of the triode VT3;

[0039] A capacitor C6 is provided between the power output point and the ground wire.

[0040] The parallel design of TVS diode VD4 and resistors R11 / R12 forms a transient voltage suppression barrier, which can quickly clamp the voltage when a surge appears at the power output point; capacitor C6 further absorbs low-frequency interference, significantly improving the surge resistance of the circuit under double protection.

[0041] Preferably, the state detection circuit includes a resistor R1. The input end of the resistor R1 is connected to the reference level of the single-chip microcomputer, and the output end of the resistor R1 is connected to the AD detection port after passing through a resistor R4. A grounded C4 is provided between the resistor R4 and the AD detection port.

[0042] The output end of the resistor R1 is also connected to a diode VD1. One end of the diode VD1 is connected to the resistor R1 and the resistor R4, and the other end is connected to a resistor R8. One end of the resistor R8 is connected to the diode VD1 and the drain of the MOS transistor VM1, and the other end is connected to the power output point. The voltage division structure of resistors R1 and R4, combined with the low-pass filtering characteristics of capacitor C4, can filter out high-frequency noise in the AD detection port signal, improving the sampling accuracy of the single-chip microcomputer for the power supply state and ensuring the accuracy of abnormal detection.

[0043] The state detection circuit further includes a TVS diode VD2, a TVS diode VD3, a resistor R7, and a triode VT2. The TVS diode VD2 and the TVS diode VD3 are connected in series and then connected in parallel across the resistor R8. The TVS diode VD2, the TVS diode VD3, and the resistor R7 are connected in series in turn and then connected in parallel across both ends of the emitter and the base of the triode VT2.

[0044] The unidirectional conduction characteristic of the diode VD1 can block the interference of reverse current to the state detection circuit, and the resistor R8 is linked with the drain of the MOS transistor to reflect the change of load current in real time, realizing the rapid identification and isolation of fault current.

[0045] Preferably, the state detection circuit further includes a resistor R6. One end of the resistor R6 is connected to the collector of the triode VT2, and the other end is grounded after passing through a resistor R9. A single-chip microcomputer detection pin is connected between the resistor R6 and the resistor R9;

[0046] A capacitor C5 is connected in parallel with the resistor R9.

[0047] The series connection of TVS diode VD2 and TVS diode VD3 provides multi-stage voltage clamping protection. The resistor R7 and the triode VT2 constitute an overvoltage-triggered turn-off mechanism, automatically cutting off the signal path when an abnormal high voltage is detected to prevent high voltage from flowing back and damaging the single-chip microcomputer.

[0048] The voltage-dividing network of resistor R6 and resistor R9, in conjunction with the filtering function of capacitor C5, provides a smooth and proportionally adjustable voltage signal for the microcontroller's detection pin, avoiding misjudgment caused by signal jitter and simplifying the processing burden of the microcontroller's software filtering algorithm.

[0049] As Figure 2 shown, the wiring method of the active output power supply circuit is a relatively common method at present. Devices that require a power signal to start on-site are connected to the fire alarm controller through two power lines.

[0050] In one case, a short-circuit fault occurs in the power connection line between the fire alarm controller and the on-site device. When a fire alarm occurs on-site, the controller turns on the power signal output to start the on-site device. Due to the short circuit of the power line, the power supply of the controller is pulled down and cannot work properly, and there is even a possibility of being burned out. And the on-site device cannot be started normally at this time.

[0051] In another case, an open-circuit fault occurs in the power connection line between the fire alarm controller and the on-site device. After the controller turns on the power signal output, the power signal cannot be normally supplied to the on-site device, resulting in abnormal startup. Both cases will cause the problem that the device cannot be started during a fire alarm, posing a serious fire safety hazard.

[0052] The traditional line status detection circuit can detect short-circuit faults through overcurrent detection after the power signal output is completed. This method can quickly locate faults after the output. However, it cannot detect line faults in the first time during daily monitoring and needs to wait until a fire alarm occurs to discover the line problems on-site.

[0053] To improve the reliability of on-site device startup, a function for judging abnormal line status detection (i.e., the abnormal detection circuit of this application) is added inside the controller to continuously monitor the line status of the power output line and report the fault type in the first time when a short-circuit or open-circuit fault occurs in the power connection line. The staff can conduct line fault troubleshooting and elimination according to the fault type feedback by the line status detection to ensure that the on-site device can be started normally when a fire alarm occurs.

[0054] The power output control circuit controls the gate and source voltages of the MOS transistor VM1 by controlling the switch of the triode VT3, so as to perform the power output control function. At this time, the base voltage of the triode VT3 is at a high level, and it is regulated to the matching voltage of the single-chip microcomputer through the TVS diode VD4. The pin of the single-chip microcomputer switches to the input detection state, and the power signal is at a high level in the normal output state (that is, there is no short-circuit abnormality). This part of the circuit also has the function of detecting the abnormal state of line short circuit. When there is a short circuit in the power output line, the power output current will be instantly increased. When the current exceeds the set value, the voltage drop generated by the current passing through the resistor R2 reaches the turn-on voltage of the triode VT1, making the gate and source voltages of the MOS transistor VM1 equal, and the MOS transistor VM1 turns off, playing the role of cutting off the power signal output. At this time, the base voltage of the triode VT3 is pulled down to a low level, and the single-chip microcomputer can detect the abnormal signal and judge the short-circuit abnormality of the power signal line.

[0055] When the power signal has no output, in the line state detection circuit, if the connected line is in a normal state, at this time, a specified resistor is crimped at the end field device end of the line (that is, on the side of the circuit to be measured). At this time, the resistors R1, R8 and the field-crimped resistor divide the voltage, and the resistor R4 is connected to the AD detection port of the single-chip microcomputer to detect the normal level. When a short-circuit fault occurs in the line, the resistors R1 and R8 divide the voltage, and the AD detection port of the single-chip microcomputer detects a low level, which is the short-circuit fault level. When an open-circuit fault occurs in the line, the resistor R4 is directly pulled up to a high level, and the AD detection port of the single-chip microcomputer detects the open-circuit fault level. The three state levels in the case of no power signal output started can be distinguished. In addition, after the power signal is started in this part of the circuit, if the field is in a normal wiring state, the power output flows through the TVS diodes VD2 and VD3, and the voltage drops of the two diodes turn on the triode VT2. At this time, the resistors R6 and R9 divide the voltage, and the divided voltage position is connected to the detection pin of the single-chip microcomputer. At this time, a high level is detected and it is judged that the circuit is normal. At this time, if an open-circuit abnormality occurs in the field line, no current passes through the TVS diodes VD2 and VD3, the triode VT2 turns off, and the detection pin of the single-chip microcomputer at the divided voltage position of the resistors R6 and R9 detects a low level, and it is judged that the line is in an open-circuit state.

[0056] Furthermore, this embodiment also provides the test data of this abnormal detection circuit as shown in the following table:

[0057]

Claims

1. An abnormal detection circuit for fire monitoring, the abnormal detection circuit is arranged between a single-chip microcomputer and a circuit to be detected, and is characterized in that: It includes a power output control circuit and a status detection circuit; The power output control circuit is provided with an MOS transistor VM1, a triode VT1, and a triode VT3. The base of the triode VT3 is connected to the control / detection port. The collector of the triode VT3 is connected to the gate of the MOS transistor VM1. The base and the collector of the triode VT1 are respectively connected in parallel to the gate and the source of the MOS transistor VM1; The status detection circuit is arranged between the power output control circuit and the single-chip microcomputer.

2. The abnormal detection circuit for fire monitoring according to claim 1, wherein: The power output control circuit includes a capacitor C2 and a resistor R3. The capacitor C2 is arranged at the front end of the resistor R3. One end of the capacitor C2 is connected to the input power supply VCC, and the other end is grounded. The resistor R3 is connected in parallel across the emitter and the collector of the triode VT1.

3. The abnormal detection circuit for fire monitoring according to claim 2, characterized in that: A capacitor C3 is connected in parallel between the emitter and the base of the triode VT1. A resistor R5 is connected in series with the capacitor C3. A resistor R2 is connected in parallel with the capacitor C3 and the resistor R5. A capacitor C1 is connected in parallel with the resistor R2.

4. The abnormal detection circuit for fire monitoring according to claim 3, wherein: A resistor R5 is connected in parallel between the gate and the source of the MOS transistor VM1, the base and the collector of the triode VT1.

5. The abnormal detection circuit for fire monitoring according to claim 3, wherein: A resistor R10 is arranged between the base of the triode VT3 and the power output point.

6. The abnormal detection circuit for fire monitoring according to claim 5, characterized in that: A TVS diode VD4, a resistor R11, and a resistor R12 are connected in parallel between the base and the emitter of the triode VT3; A capacitor C6 is arranged between the power output point and the ground wire.

7. An anomaly detection circuit for fire monitoring according to any one of claims 1-6, characterized in that: The status detection circuit includes a resistor R1. The input end of the resistor R1 is connected to the reference level of the single-chip microcomputer. The output end of the resistor R1 is connected to the AD detection port after passing through a resistor R4. A grounded C4 is arranged between the resistor R4 and the AD detection port.

8. An abnormal detection circuit for fire monitoring according to claim 7, characterized in that: The output end of the resistor R1 is also connected to a diode VD1. One end of the diode VD1 is connected to the resistor R1 and the resistor R4, and the other end is connected to a resistor R8. One end of the resistor R8 is connected to the diode VD1 and the drain of the MOS transistor VM1, and the other end is connected to the power output point.

9. An abnormal detection circuit for fire monitoring according to claim 8, characterized in that: The status detection circuit also includes a TVS diode VD2, a TVS diode VD3, a resistor R7, and a triode VT2. The TVS diode VD2 and the TVS diode VD3 are connected in series and then connected in parallel across the resistor R8. The TVS diode VD2, the TVS diode VD3, and the resistor R7 are connected in series in turn and then connected in parallel across the emitter and the base of the triode VT2.

10. The abnormal detection circuit for fire monitoring according to claim 8, characterized in that: The status detection circuit also includes a resistor R6. One end of the resistor R6 is connected to the collector of the triode VT2, and the other end is grounded after passing through a resistor R9. A single-chip microcomputer detection pin is connected between the resistor R6 and the resistor R9; A capacitor C5 is connected in parallel with the resistor R9.

Images